Prove that following problem is complete in NP in sense of Karp.
Given: context free grammar $G$
Check if $G$ generates word containing all symbols from alphabet
Remark Above problem should be encoded as langauge over finite alphabet, although alphabet of $G$ can be arbitrarily big. You can assume that symbols of this alphabet are encoded as binary strings.
My main problem at this moment is that I don't understand Remark. For me, it should be attached also alphabet of grammar. Can you explain me in human language what this Remark try to say ?
To be more clear I can say that in other task with the same question, but with given regex and alphabet of regex I did deal with it. However, in mentioned task there was no this awkward Remark.